نتایج جستجو برای: Urban canyon positioning

تعداد نتایج: 217374  

Abstract: Urban canyon is categorized as hard environment for positioning of a dynamic vehicle due to low number and also bad configuration of in-view satellites. In this paper, a tuning procedure is proposed to adjust the important factors in Kalman Filter (KF) using Genetic Algorithm (GA). The authors tested the algorithm on a dynamic vehicle in an urban canyon with hard condition and compare...

2001
Youjing Cui Shuzhi Sam Ge

The Global Positioning System (GPS) has been widely used in land vehicle navigation applications. However, the positioning systems based on GPS alone face great problems in the so called urban canyon environments where the GPS signals are often blocked by high buildings and there are not enough available satellites signals to estimate the positioning information of a x. To solve the problem, a ...

2004
S. Syed

Accurate vehicle location is important for various Intelligent Transportation System (ITS) applications such as route guidance and collaborative driving. The Global Positioning System (GPS) has become popular for locating vehicles for many ITS applications due to the 24hour, all weather and free-of-charge availability. Although GPS-based vehicle navigation systems are accurate in open sky condi...

2009
Thomas GALLAGHER Binghao LI Allison KEALY Andrew G DEMPSTER

It is now widely accepted that GPS meets, under ideal operational conditions, all attributes of a ubiquitous positioning system, i.e. accuracy, reliability and availability. However, its performance quickly deteriorates in certain environments, such as indoors or in urban canyons. In such environments, the demand for location based services (LBS) is growing exponentially, mainly because of the ...

2014
Chengliang Huang Xiao-Ping Zhang

Nowadays, GPS (Global Positioning System) has been widely used to position airplanes, ships, automobiles, migrating animals, and human beings, etc. However, GPS has its own limitations. Other than the user groups for whom GPS is operated, there is no service level agreement with anyone else. As more and more people become dependant on GPS in more and more countries, the political control of GPS...

2010
Binghao Li Yong Khing Tan Andrew G. Dempster

It is well known that a GPS receiver needs to “see” at least four satellites to provide a 3D fix solution. But in difficult environments such as an urban canyon, the number of “visible” satellites is often not enough. WiFi signals have been utilized for positioning mainly based on the fingerprinting technology. However, the accuracy of WiFi positioning outdoors is from several tens of meters to...

2017
K. W. OLESON G. B. BONAN J. FEDDEMA M. VERTENSTEIN C. S. B. GRIMMOND

Urbanization, the expansion of built-up areas, is an important yet less-studied aspect of land use/land cover change in climate science. To date, most global climate models used to evaluate effects of land use/land cover change on climate do not include an urban parameterization. Here, the authors describe the formulation and evaluation of a parameterization of urban areas that is incorporated ...

2003
Cheng-Hsin Chang Robert N. Meroney

The goal of this paper is to present bluff body flow and transport from steady point sources of pollutants, or chemical and biological agents in an idealized urban environment This paper includes ventilation behavior in different street canyon configurations. To evaluate dispersion in a model urban street canyon, a series of tests with various street canyon aspect ratios (B=H) are presented. Bo...

2015
Li-Ta Hsu Yanlei Gu Shunsuke Kamijo

Currently, global navigation satellite system (GNSS) receivers can provide accurate and reliable positioning service in open-field areas. However, their performance in the downtown areas of cities is still affected by the multipath and none-line-of-sight (NLOS) receptions. This paper proposes a new positioning method using 3D building models and the receiver autonomous integrity monitoring (RAI...

2015
Li-Ta Hsu Shau-Shiun Jan Paul D Groves Nobuaki Kubo

Multipath interference and non-line-of-sight (NLOS) reception are major error sources when using global navigation satellite systems (GNSS) in urban environments. A promising approach to minimize the effect of multipath interference and aid NLOS detection is vector tracking. Therefore the objective of this research is to assess vector tracking in a dense urban environment to determine its effec...

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